Material for electrode of power storage device, power storage device, and electrical appliance

Abstract

To improve the reliability of a power storage device. A granular active material including carbon is used, and a net-like structure is formed on part of a surface of the granular active material. In the net-like structure, a carbon atom included in the granular active material is bonded to a silicon atom or a metal atom through an oxygen atom. Formation of the net-like structure suppresses reductive decomposition of an electrolyte solution, leading to a reduction in irreversible capacity. A power storage device using the above active material has high cycle performance and high reliability.

What is claimed is: 
     
       1. A material for an electrode of a power storage device comprising:
 a granular active material comprising a carbon atom; and 
 a film having a structure over the granular active material, 
 wherein the structure comprises a plurality of bonds between the carbon atom and one of a silicon atom and a metal atom through an oxygen atom, and 
 wherein the film partly covers a surface of the granular active material so that the surface of the granular active material has a first region which is covered with the film, and a second region which is not covered with the film. 
 
     
     
       2. The material for an electrode of a power storage device according to  claim 1 , wherein the granular active material comprises a graphite particle. 
     
     
       3. The material for an electrode of a power storage device according to  claim 1 , wherein the metal atom is one of a niobium atom, a titanium atom, a vanadium atom, a tantalum atom, a tungsten atom, a zirconium atom, a molybdenum atom, a hafnium atom, a chromium atom, and an aluminum atom. 
     
     
       4. The material for an electrode of a power storage device according to  claim 1 , further comprising a plurality of oxide layers over the film,
 wherein each of the plurality of oxide layers comprises a bond of the one of the silicon atom and the metal atom, and an oxygen atom. 
 
     
     
       5. A power storage device comprising a negative electrode, the negative electrode comprising the material for an electrode of a power storage device according to  claim 1 . 
     
     
       6. An electrical appliance comprising the power storage device according to  claim 5 . 
     
     
       7. A material for an electrode of a power storage device comprising:
 a granular active material comprising a carbon atom; and 
 a film having a structure over the granular active material, 
 wherein the structure comprises a plurality of bonds between the carbon atom and a silicon atom through an oxygen atom, and 
 wherein the film partly covers a surface of the granular active material so that the surface of the granular active material has a first region which is covered with the film, and a second region which is not covered with the film. 
 
     
     
       8. The material for an electrode of a power storage device according to  claim 7 , wherein the granular active material comprises a graphite particle. 
     
     
       9. The material for an electrode of a power storage device according to  claim 7 , further comprising a plurality of oxide layers over the film,
 wherein each of the plurality of oxide layers comprises a bond of the silicon atom and an oxygen atom. 
 
     
     
       10. A power storage device comprising a negative electrode, the negative electrode comprising the material for an electrode of a power storage device according to  claim 7 . 
     
     
       11. An electrical appliance comprising the power storage device according to  claim 10 . 
     
     
       12. A material for an electrode of a power storage device comprising:
 a granular active material comprising a carbon atom; and 
 a film having a structure over the granular active material, 
 wherein the structure comprises a plurality of bonds between the carbon atom and one of a silicon atom and a metal atom through an oxygen atom, 
 wherein the granular active material comprises a plurality of graphene layers, 
 wherein the film partly covers a surface of the granular active material so that the surface of the granular active material has a first region which is covered with the film, and a second region which is not covered with the film, and 
 wherein the structure exists at end portions of part of the plurality of graphene layers. 
 
     
     
       13. The material for an electrode of a power storage device according to  claim 12 ,
 wherein the metal atom is one of a niobium atom, a titanium atom, a vanadium atom, a tantalum atom, a tungsten atom, a zirconium atom, a molybdenum atom, a hafnium atom, a chromium atom, and an aluminum atom. 
 
     
     
       14. The material for an electrode of a power storage device according to  claim 12 , further comprising a plurality of oxide layers over the film,
 wherein each of the plurality of oxide layers comprises a bond of the one of the silicon atom and the metal atom, and an oxygen atom. 
 
     
     
       15. A power storage device comprising a negative electrode, the negative electrode comprising the material for an electrode of a power storage device according to  claim 12 . 
     
     
       16. An electrical appliance comprising the power storage device according to  claim 15 .